Question

Find the nth term of this quadratic sequence

4,7,12,19,28

Answer 1

nth term = n^2 + 3.

Explanation:

4 7 12 19 28

Differences 3 5 7 9

Differences 2 2 2

So the nth term contains n^2.

4 7 12 19 28

Values of n^2 1 4 9 16 25

Differences 3 3 3 3 3

So the nth term = n^2 + 3.